US3461285A - Mass spectrometer ion source with a two region ionization chamber to minimize energy spreading of the ions - Google Patents

Mass spectrometer ion source with a two region ionization chamber to minimize energy spreading of the ions Download PDF

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Publication number
US3461285A
US3461285A US649544A US3461285DA US3461285A US 3461285 A US3461285 A US 3461285A US 649544 A US649544 A US 649544A US 3461285D A US3461285D A US 3461285DA US 3461285 A US3461285 A US 3461285A
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grid
ions
electrode
ion source
electron beam
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Expired - Lifetime
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US649544A
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English (en)
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Helmut Wilhelm Werner Werner
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/10—Ion sources; Ion guns
    • H01J49/14—Ion sources; Ion guns using particle bombardment, e.g. ionisation chambers

Definitions

  • the ions formed being extracted from the ionization space through a small gap parallel to the direction of the electron beam by means of an electric field the direction of which extends at right angles to the direction of the electron beam, a fiat grid-like electrode being provided consisting of parallel wires which cross the direction of the electron beam, the latter electrode dividing the ionization space into two zones one of which contains the ionization gap, a potential being applied to the grid-like electrode which in combination with potentials applied to the other electrode produces a small voltage gradient in the first zone and a large voltage gradient in the other zone.
  • the invention relates to an ion source, in particular an ion source for a mass spectrometer.
  • ions are formed by ionization of a gas to be tested by means of an electron beam which is collimated by a magnetic field in the direction of the beam, the ions formed being extracted from the ionization space through a small gap parallel to the direction of the electron beam by means of an electric field the direction of which extends at right angles to the direction of the electron beam.
  • the electrons emitted by a filament are confined into a narrow beam with a comparatively weak magnetic field having values up to a few hundred Gauss.
  • a weak electric field which is at right angles to the beam the ions which are formed are extracted from the ionization space through a gap into an ion lens.
  • the extracting field which is of the order of magnitude of a few volts per centimeter is supplied by the potential of the first electrode ot the ion lens, the potential of the wall of the ionization space, and the potential of a repeller electrode inside the ionization space.
  • the repeller electrode is located so that the electron beam traverses between said electrode and the emanating gap.
  • the ion paths in the crossed electric and magnetic fields are cycloids in a plane at right angles to the direction of the magnetic field in which the factor ME occurs as a parameter where M is the mass number of the eB /i0n, E is electric field strength of the extracting field, B the magnetic field in the ionization space, and e the charge of the ion.
  • M is the mass number of the eB /i0n
  • E is electric field strength of the extracting field
  • B the magnetic field in the ionization space
  • e charge of the ion.
  • the particles having the smallest mass (M) will follow the most curved paths.
  • a flat grid-like electrode consisting of parallel wires which cross the direction of the electron beam and that of the extracting field at right angles is arranged at a distance of a few tenths of a millimeter from the ionization area.
  • This electrode divides the ionization space into two areas the first of which comprises the emanating gap.
  • a potential is applied to that electrode which, in combination with the potentials of the extracting electrodes, produces a small potential gradient which is a maximum of a few volts per centimeter in the first area, and produces a large potential gradient which is at least some tens of volts per centimeter in the second area.
  • the repeller electrode has a small positive potential with respect to the grid which is not more than a few volts.
  • the flat front wall of the ionization space in which the emanating gap is located has a negative potential with respect to the grid of the order of tens of volts. Consequently, a strong field which is formed as a result of the grid and, possibly, also by the potentials of electrodes of the ion lens between the grid and the front wall does not penetrate too much into the area which is restricted by the grid and the housing of the ionization space which consists of a flat rear wall opposite to the emanating gap and a box-like part of the wall which has the rear wall as a base.
  • the repeller electrode is connected to the housing and the grid is insulated from the surrounding parts.
  • the grid is connected to the housing and the repeller electrode is insulated from the surrounding parts.
  • both the repeller electrode and the grid are connected to the housing.
  • the ions are then extracted from the ionization area by the penetrating field of the front wall which has a negative potential with respect to the housing of a few hundred volts.
  • the grid is supported by a holder.
  • a construction is used in which the wall of the said holder is,
  • the ions need cover only a very short distance, namely at a maximum the thickness of the ionization area plus the distance from the ionization area to the grid.
  • the deviation as a result of the collimating magnetic field is still small.
  • such a small potential gradient prevails that the energy spreading of the ions is not larger than in the conventional sources.
  • FIGURE 1 is a cross-sectional view normal to the electron beam of a part of the ion source and the ion lens inside the vacuum envelope.
  • FIG. 2 shows part of FIG. 1 on an enlarged scale, equipotential lines also being shown.
  • the cross-section of the electron beam is denoted by the area 1 in which the ions are formed.
  • the proportions of this area gradually increase from 2 mms. 0.5 mm. to 4 mms. 2 mms.
  • the cross-section shown in FIG- URE l is chosen to be such that the upper limit of these dimensions 4 mms. 2 mms. is shown.
  • the collimating magnetic field has a strength of 150 Gauss and is denoted by B in the figure.
  • the ionization space is limited by a flat front wall 2 which comprises an emanating gap 3, having a length of 10 mms. and a width of 1 mm., and a housing consisting of a flat rear wall 4 and a box-like part 5.
  • the ionization space comprises a repeller electrode 6 and a grid-like electrode 7 which is located at a distance of 8 mms. from the rear wall 4, at a distance of 2.5 mms. from the front wall 2 and at a distance of 0.5 mm. from the area 1.
  • the grid is secured to a molybdenum frame and consists of tungsten wires, 25,11. thickness, mutual distance approximately The wires are arranged at right angles to the direction of the electron beam in order to prevent the structure of the grid from appearing in the ion spectrum.
  • the grid is supported by a holder 8 which widens in the direction of the gap 3.
  • the ion lens is constituted by the electrodes 9, 10, 11, 12, 13, 14 and 15.
  • the electrode 15 includes a slot 16 affording access to the analyzer space.
  • the numbers in brackets indicate the potentials with respect to the housing on the lines and electrodes at the applied voltages.
  • the repeller electrode 6 is at a potential of 0 volts with respect to the housing of the ionization space.
  • the grid 7 is at a potential of l.7 volts with respect to the housing.
  • the front wall 2 is at 30 volts with respect to the housing.
  • the electrode pair 9 and 10 is at 500 volts with respect to the housing and the electrode 11 is at -2000 volts with respect to the housing.
  • the potential of the housing with respect to ground is determined by the potential difference between the electrodes 11 and 15 from FIG. 1, the latter of which is at ground potential.
  • the potential gradient at these voltages is only 3.5 volts per centimeter, but in the area between the grid 7 and the front wall 2 the potential gradient at these voltages is volt per centimeter.
  • an ion source for a mass spectrometer the combination of a housing closed at one end by a wall having an aperture therein for the passage of ions, means within said housing for producing an electron beam in a given direction for ionizing a gas in said housing, means to produce a magnetic field in said given direction, means to produce an electric field in said housing in a direction perpendicular to said given direction for extracting ions through said aperture, a grid-like electrode within said housing having parallel wire-like elements intersecting the direction of the electron beam, said grid-like electrode being positioned between said wall having the apert-ure therein and said electron beam and being spaced further from said wall than from said electron beam, said grid-like electrode being spaced a distance from said electron beam of the order of tenths of a millimeter, said grid-like electrode dividing the interior of said housing into two zones one of which contains the electron beam, means to produce a potential gradient in a first zone containing the electron beam not exceeding the order of volts per centimeter
  • An ion source as claimed in claim 1 in which a repeller electrode is positioned in the first zone on the opposite side of the electron beam from the grid-like electrode, a potential being applied between said electrodes for producing the potential gradient in said first zone.
  • An ion source as claimed in claim 2 in which the repeller electrode and the grid-like electrode are connected to the housing.
  • An ion source as claimed in claim 2 in which the grid-like electrode is supported by a conductive holder 1 which widens in the direction of the emanating gap.
  • Anion source as claimed in claim 1 including an ion lens in said second zone in which potential differences exist between deflection electrodes on either side of the axis of the ion lens which are not more than a few volts.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Tubes For Measurement (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
US649544A 1966-07-02 1967-06-28 Mass spectrometer ion source with a two region ionization chamber to minimize energy spreading of the ions Expired - Lifetime US3461285A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6609292A NL6609292A (fr) 1966-07-02 1966-07-02

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US3461285A true US3461285A (en) 1969-08-12

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US649544A Expired - Lifetime US3461285A (en) 1966-07-02 1967-06-28 Mass spectrometer ion source with a two region ionization chamber to minimize energy spreading of the ions

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US (1) US3461285A (fr)
JP (1) JPS5032638B1 (fr)
CH (1) CH470757A (fr)
DE (1) DE1598884A1 (fr)
GB (1) GB1190451A (fr)
NL (1) NL6609292A (fr)
SE (1) SE329216B (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016421A (en) * 1975-02-13 1977-04-05 E. I. Du Pont De Nemours And Company Analytical apparatus with variable energy ion beam source
US4166952A (en) * 1978-02-24 1979-09-04 E. I. Du Pont De Nemours And Company Method and apparatus for the elemental analysis of solids
US6037587A (en) * 1997-10-17 2000-03-14 Hewlett-Packard Company Chemical ionization source for mass spectrometry
WO2008047155A1 (fr) * 2006-10-19 2008-04-24 Smiths Detection-Watford Limited Dispositif spectrométrique
WO2007097920A3 (fr) * 2006-02-15 2008-08-07 Varian Inc Spectromètre de masse à source ionique sans fente à sensibilité élevée
US20100003866A1 (en) * 2008-07-04 2010-01-07 Peter Dent Electrical Connectors
US20100012834A1 (en) * 2006-12-20 2010-01-21 Stephen John Taylor Gas Pre-Concentrator for Detection Apparatus
US20100012833A1 (en) * 2006-12-20 2010-01-21 Stephen John Taylor Detector Apparatus and Pre-Concentrator
US20100308216A1 (en) * 2006-11-04 2010-12-09 Alastair Clark FAIMS Ion Mobility Spectrometer With Multiple Doping
US8668870B2 (en) 2006-12-20 2014-03-11 Smiths Detection-Watford Limited Ion mobility spectrometer which controls carrier gas flow to improve detection
US8734722B2 (en) 2006-12-20 2014-05-27 Smiths Detection-Watford Limited Detection apparatus accompanying preconcentrated pulsed analyte via an aperture
WO2020014571A1 (fr) * 2018-07-12 2020-01-16 Perkinelmer Health Sciences, Inc. Source d'ions à impact électronique dynamique
US11328919B2 (en) * 2018-05-11 2022-05-10 Leco Corporation Two-stage ion source comprising closed and open ion volumes

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938116A (en) * 1956-04-02 1960-05-24 Vard Products Inc Molecular mass spectrometer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938116A (en) * 1956-04-02 1960-05-24 Vard Products Inc Molecular mass spectrometer

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016421A (en) * 1975-02-13 1977-04-05 E. I. Du Pont De Nemours And Company Analytical apparatus with variable energy ion beam source
US4166952A (en) * 1978-02-24 1979-09-04 E. I. Du Pont De Nemours And Company Method and apparatus for the elemental analysis of solids
US6037587A (en) * 1997-10-17 2000-03-14 Hewlett-Packard Company Chemical ionization source for mass spectrometry
WO2007097920A3 (fr) * 2006-02-15 2008-08-07 Varian Inc Spectromètre de masse à source ionique sans fente à sensibilité élevée
WO2008047155A1 (fr) * 2006-10-19 2008-04-24 Smiths Detection-Watford Limited Dispositif spectrométrique
US8648296B2 (en) 2006-10-19 2014-02-11 Smiths Detection-Watford Limited Spectrometer apparatus
US8405023B2 (en) 2006-10-19 2013-03-26 Smiths Detection-Watford Limited Spectrometer apparatus
US8222595B2 (en) 2006-10-19 2012-07-17 Smiths Detection-Watford Limited Spectrometer apparatus
US20100308216A1 (en) * 2006-11-04 2010-12-09 Alastair Clark FAIMS Ion Mobility Spectrometer With Multiple Doping
US8668870B2 (en) 2006-12-20 2014-03-11 Smiths Detection-Watford Limited Ion mobility spectrometer which controls carrier gas flow to improve detection
US8734722B2 (en) 2006-12-20 2014-05-27 Smiths Detection-Watford Limited Detection apparatus accompanying preconcentrated pulsed analyte via an aperture
US8158933B2 (en) 2006-12-20 2012-04-17 Smiths Detection-Watford Limited Detector apparatus and pre-concentrator
US9664657B2 (en) 2006-12-20 2017-05-30 Smiths Detection—Watford Limited Pulsed admission of analyte to detection apparatus
US20100012833A1 (en) * 2006-12-20 2010-01-21 Stephen John Taylor Detector Apparatus and Pre-Concentrator
US20100012834A1 (en) * 2006-12-20 2010-01-21 Stephen John Taylor Gas Pre-Concentrator for Detection Apparatus
US9513256B2 (en) 2006-12-20 2016-12-06 Smiths Detection-Watford Limited Ion mobility spectrometer which controls carrier gas flow to improve detection
US8022360B2 (en) 2006-12-20 2011-09-20 Smiths Detection-Watford Limited Gas pre-concentrator for detection apparatus
US20100003866A1 (en) * 2008-07-04 2010-01-07 Peter Dent Electrical Connectors
US7841906B2 (en) 2008-07-04 2010-11-30 Smiths Group Plc Electrical connectors
US11328919B2 (en) * 2018-05-11 2022-05-10 Leco Corporation Two-stage ion source comprising closed and open ion volumes
WO2020014571A1 (fr) * 2018-07-12 2020-01-16 Perkinelmer Health Sciences, Inc. Source d'ions à impact électronique dynamique
US10879030B2 (en) 2018-07-12 2020-12-29 Perkinelmer Health Sciences, Inc. Dynamic electron impact ion source
US11276544B2 (en) 2018-07-12 2022-03-15 Perkinelmer Health Sciences, Inc. Dynamic electron impact ion source

Also Published As

Publication number Publication date
DE1598884A1 (de) 1971-04-01
GB1190451A (en) 1970-05-06
CH470757A (de) 1969-03-31
NL6609292A (fr) 1968-01-03
JPS5032638B1 (fr) 1975-10-22
SE329216B (fr) 1970-10-05

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